Finding the Fourth Proportional to 1,665.06, 2,496.45 and 1,086.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,665.06 : 2,496.45 = 1,086.78 : x
2. Step 2: Convert to fraction form
   1,665.06/2,496.45 = 1,086.78/x
3. Step 3: Cross multiply
   1,665.06x = 2,496.45 × 1,086.78
4. Step 4: Simplify right side
   1,665.06x = 2,713,091.93
5. Step 5: Solve for x
   x = 2,713,091.93/1,665.06
6. Step 6: Final answer
   x = 1,629.43